Field of the Invention
The following disclosure relates to an adsorbent for carbon dioxide and a method for preparing the same. More particularly, the following disclosure relates to an adsorbent for carbon dioxide that has excellent adsorption/desorption characteristics even at room temperature under ambient pressure and shows significantly high selectivity to nitrogen gas, as well as to a method for preparing the same.
Description of the Related Art
In the case of industrial exhaust gas, separation (isolation) of CO2 (carbon dioxide) is regarded as one of the most important technologies for realizing the green and sustainable future. It is required that the properties of a material for separation of carbon dioxide are evaluated under two extreme working conditions, i.e., adsorption and desorption conditions.
Due to the necessity for a nanomaterial having high CO2 storage capacity, desorption phenomena are often ignored. In this context, a fundamental problem occurs because of interdependence between CO2 affinity and selectivity. According to the present disclosure, the principle of gelling is used to provide the surface of porous graphene with two-dimensional graphitic C3N4(g-C3N4). By virtue of the presence of micropores formed from non-coplanar edges, it is possible to provide an optimal region between chemical adsorption and physical adsorption. The material according to the present disclosure shows improved carbon dioxide adsorptivity (0.43 mmol·g−1) and high selectivity to nitrogen (α12ads=113) at room temperature, and still has desorption capability (R=98%) to the captured carbon dioxide.
Basically, in the calculation based on a density function, the principle of interaction between carbon dioxide and g-C3N4 is classified into interaction between dipole and induced dipole. According to the present disclosure, there is provided an adsorbent for CO2 that allows easy adsorption and desorption of carbon dioxide from materials abundant in the earth.
Post-combustion gas from power plants, i.e. exhaust gas occupies 40% or more of the total emission of CO2. Effective control of exhaust gas is significantly important in view of provision for global warming and sustainable supply of energy. Currently, control of industrial exhaust gas is largely based on wet chemical adsorption using an alkanolamine solvent.
Unfortunately, separation of CO2 and that of such a solvent require a significantly large amount of energy (up to 30% of the total energy production). In addition, there is a problem of an increase in cost due to a corrosive operating condition. Although there has been a study about a metal organic framework partially containing zeolite as a substitute material, there are problems in that an expensive transition metal catalyst is used and regeneratability is low due to high adsorption energy.
Strong adsorption energy is an important factor for a high degree of capture for carbon dioxide. However, it inevitably results in desorption of carbon dioxide and an increase in regeneration energy. An ideal adsorbent for carbon dioxide should have high regeneratability in an easy carbon dioxide adsorption/desorption mechanism and adequate adsorption energy.